问题详情

What can we know about the present epidemic ---swine flu？
A) The genes of the flu virus come from pigs.
B) It will soon spread and cause a pandemic.
C) There has been further change in the genes of the viruses.
D) It is similar to the influenza pandemic of 1918 to 1919.请帮忙给出正确答案和分析，谢谢！